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No. 620,807. Pafentd Mar. 7, |899- W. M. SMITH.

STEAM GENERATOR. (Application led Dec. 21, 1897. (No Model.) 4Sheets-Sheet I.

me Nozms vrins co.. PHoTo-LITNQ.. wAsmNoToN. D. cv

No. 620,807. V Patented Mar. 7, |899. w. M. SMITH.

STEAM GENERATOR.

(Application med me. 21, i897.) l(N0 Model.) 4 Sheets-Sheet 2.

Q Q S s THE Nonms Parns co. PNOTQLWNO.. WASHINGTON, o. c.

N0. 6205807- T Patented Mar.`7, |899.

W. M. SMITH.

STEAM GENERATOR.

(Application led Dec. 21, 1897.) (No Model.) 4 Sheets- Sheet 3.

No. 620,807. Patented Mar. 7, |899. W. M. SMITH.

l STEAM GENERATOR.

(Application filed Dec. 21, 1897.)

4 Sheets-Sheet 4.

(No Model.)

we miams Pfrzns cu., momuyno.. wummou o c UNITEDv STATES PATENTl OEEICE.

VALTER MACKERSIE SMITH, OF NEWCASTLE-UPON-TYNE, ENGLAND.

STEAM-GEN ERATO R.

SPECIFICATION forming part of Letters 'Patent N0. 620,807', dated March7, 1899. d Application filed December 21,1897. Serial No. 662,877. (Nmodel l To @ZZ whom it may concern,.-

Beit known that I, WALTER MACKERSIE SMITH, a subject of the Queen ofGreat Britain and Ireland, residing at J esmond, Newcastleu upon-Tyne,in the county of N orthurnberland, England, have invented Improvementsin Steam-Generators, of which the following is a specification.

This invention has reference to improve# ments in steam-generators ofthe locomotive type. Accordingthereto the fire-box of such asteam-generator is provided with watert-ubes arranged to connect thewater-space at one point with that at another, so as to obtain increasedheating-surface and better water circulation. The water-tubes arepreferably curved and may connect points on the same side, oppositesides, sides and rear end, or sides and rear end with the roof of thetire-box. They may be connected to the rebox shell by coupling devicesor unions, so

as to be removable from the interior of the tire-box through thetire-door opening, orthey may be inserted through holes in the inner andouter shells of the fire-box and be fixed in the inner shell byexpanding, the holes in the outer shell being provided with movableclosures for gaining ready access to the tube ends.

In the accompanying illustrative drawings, Figure lis a longitudinalsection on the line m of Fig. 2; and Fig. 2 is a transverse s ection onthe line y y of Fig. 1, showing the nre-box portion of a steam-generatorof the locomotive type with one arrangement of water-tubes having theirends connected to the inner walls of the irebox by coupling devicesaccording to this invention. Figs. 3 and 4 show a hre-box with modifiedarrangements of water-tubes according to this invention, Fig. 3 being acentral longitudinal section on the line as of Fig. 4, and Fig. 4 beinga sectional plan on the line z z of Fig. 3. Fig. 5 is a centrallongitudinal section; and Fig. 6, an end view showing, to alarger scalethan Figs. l to 4, inclusive, a tube end with coupling device forconnecting the same to the shell ot the fire-box. Figs. '7 and 8, Figs.9 and 10, Figs. 11 and 12,- and Figs. 13 and 14 are similar views toFigs. 5 and 6, showing modiiied arrangements of coupling devices.4

Referring to Figs. 1 and 2 of the drawings,

l is the outer shell of the fire-box, 2 the in- .ner shell of thefire-box, and 3 curved waterflame and hot gas to pass around and betweenI do not confine myself to any particular shape of the tubes, nor do Ivlimit myself to any particular point in the sides or crown of theire-b0x at which to insert the tubes.

They may be continued down near to the bottom of the fire-box, as shownby dotted lines at 3* in Fig. 2. In this case the plate forming theinner shell 2 may be bulged inward, as shown at 2n, so as to formprojections in which the lower ends of the tubes 3* can be secured, or asuitable junction-pipe, such as 2b, may be fixed at its ends to theadjacent side of the fire-box, and to it the lower ends of the tubes 3*can be lixed. The number of tubes shown inr Fig. l is seventeen, ninebeing connected to one side of the fire-box and eight to the other side.The number and also the size of the tubes can, however, be varied so asto provide the amount of extra heatingsurface required'.

The water-tubes 3 are shown in Fig. 3 as inclined to the horizontal, theangle being such as to cause free circulation of the water in the tubesand the water-space 5 between the inner and outer shells l and 2. Thetubes at the upper part of Fig. 4 are shown as connected to diierentparts of the same side plate of the inner fire-box shell 2. The tube 3at the lower part of Fig. 4 is shown as fixed at one end to one side ofthe inner fire-box shell and at the other end to the rear end plate 2aof the said inner fire-box shell. Fig. 3 shows in dotted lines therearward ends of a number of tubes so continued to the end plate 2. Thetubes may also be arranged to cross from. one side of the tire-box tothe other side, as

indicated in dotted lines at 3f* in Fig. 2. They.'

may also be arranged to connect the rear end wall 2 to the roof of thefire-box, as indicated by dotted lines at 3b in Fig. 1. The points wherethe ends of the tubes are connected to the plate or plates forming theinner shell of the re-box may be arranged nearer to or farther from thelongitudinal center line or transverse center line 'y' y' of thefire-box, as indicated, for example, by the pipes 3. (Shown in dottedlines in Fig. 4.)

The shape of the tubes as seen in plan may be variously modified, asindicated in Fig. 4, which shows several dierent shapes the tubes mayassume; but they are preferably so arranged as to interfere as little aspossible with free access to the boilertubes. The tubes may be so bentthat they can be placed in position by being passed through suitableholes in the inner and outer shells, the ends of the tubes beingsuitably fixed in the holes in the inner Sheik-as, for example, byexpanding them by a tube-expander. inserted from the outside ot thefire-box through the holes in the outer shell l. Fig. 4 shows the tubeends thus fixed by expanding them in the shell 2 of the fire-box. Inthis case the holes in the outer shell l, through which the tubes areinserted, are made larger than those in the inner shell and are fittedwith removable closures, such as screw-plugs 4 or covers or doors 4,which admit of ready access being gained to the tubes for the purpose ofexamining, cleaning, and removing them and for further tightening uptheir ends in the inner shell 2 when desired.

Instead of fixing the ends of the water-tubes by expanding them in holesin the walls and crown of the {ire-box, as hereinbefore described, Iprefer to connect them to the lirebox by couplings or unions, whichenable the tubes to be readily detached and removed when necessarythrough the fire-door opening 8. In this case the removable closures 4 4are dispensed with.

Figs. 5 and 6 show one form of coupling suitable for this purpose. Itcomprises a hollow screw plug or nipple 9, (hereinafter called a plug,)which is screwed tightly into a thickened part of the fire-box shell 2and pro; jects into the lire-box, and a nut l0, which is screwed ontothe inwardly-projecting end of the plug and also onto the thickenedadjacent end 3 of the water-tube 3. The screwed part of the plugprojecting into the fire-box is made larger in diameter than thelscrewed part of the tube 3, and the pitch of the screwthread thereon isalso made greater than that on the tube. The two screw-threads on thenut are made the one to lit the plug and the other to it the tube. Toiix the tube end in place,the nut is run back onto the tube,which isplaced in position, after which the nut l0 is run forward onto the plugand screwed up tight.' As the screw-thread on the latter is coarser thanthat on the tube end, the conical end of the tube is drawn tightly intoor against a conical seat 9n on the plug, thus forming a steam-tightjoint. By screwing back the nut the tube end can be readily detached.

Figs. 7 and 8 show a modification in which the tube end :is providedwith a collar 3e, by which its coned end is forced into close con' tactwith the coned end of the plug 9 by the flange l0 of the coupling-nutI0. The collar is preferably formed on a sleeve 3f, screwed tightly ontothe tube end.

In the arrangement shown in Figs. 9 and l0 the tube end has fixed toitin a duid-tight manner an externally-screw-threaded sleeve Il, having aconed end Il, which is fixed in place by passing it through the hole inthe fire-box plate 2 when the plug 9 is removed, then screwing the saidplug through the hole until it bears in a water-tight manner against theconed end ll"L of the sleeve, and finally screwing the nut 10 on thesleeve until it bears in a steam-tight manner against the plug.

Figs. ll and l2 show a modification somewhat like that illustrated inFigs. 9 and 10, except that the plug 9 screws onto the sleeve Il, whichis made shorter andis unprovided with a nut.

Figs. I3 and 14 show another modification, in which the tube end isoutwardly :flared or coned and the interior of the plug 9 is i11- wardlyconed, and a ferrule or ring I2, coned externally and internally to itthe plug and tube end, respectively, is forced into close contact witheach of them, so as to make a IOO steam-tight joint with both and holdthe tube end in place by a forcing-nut l0, screwed into the plug 9. Theouter end of the plug may be formed, as shown in dotted lines, to serveas an abutment for the tube end.

With each arrangement the tube end is released by simply screwing backthe nut IO in Figs. 5 to 8, inclusive, and Figs. 13 and I4, the nut l0and plug 9 in Figs. 9 and IO, and the plug 9 in Figs. Il and l2.

I am aware that the tube-plate in the {irebox of a locomotive-boiler hasheretofore been connected to the rear end wall 2 of the firebox byrearwardly and upwardly inclined water-tubes, upon which the brick archhas sometimes been placed; also,that the said tube plate has beenprovided with a rearwardly and upwardly inclined water-chamber connectedby tubes to the rear end plate 2*L of the IIO noprovision has been madeto admit of such tubes being easily and readily removed and replacedwithout the necessity of taking the boiler to pieces. This drawback isovercome by employing the couplings or union hereinbefore described.

What I claim is-' I. Ina steam-generator of the locomotive type, thecombination with the inner shell of the fire-box, of a series of benttubes within the iire-box on either side secured at their ends in saidshell and extending obliquely from the forward end of the box toward therearward end, whereby access to the lines is unobstructed and eiiicientcirculation of the water between the shells forming the walls of thelire-box is effected.

2. In a steam-generator of the locomotive type, the combination with thefire-box of such generator, of water-tubes located within said iire-box.and each of which has its ends connected to the portion of the innershell of the fire-box in rear of the tube-plate, so as to be in freecommunication with the waterspace formed by and between the inner andouter shells of said fire-box, all of said tubes being so arranged as toadmit of free and unobstructed access to the boiler-tubes from thetire-door, substantially as described.

3. In a steam-generator of the locomotive type, the combination with thetire-box of such a generatonof water-tubes located within 'said {ire-boxand havingtheir ends connected to the portion of the inner shell of thefirebox in rear of the tube-plate, so as to be in free communicationwith the water space formed by and between the inner and outer shells ofsaid fire-box, and coupling devices whereby the ends of said tubes canbe readily connected to and disconnected from the 7 said inner shellfrom the inside of said firebox, substantially as described.

4. In a steam-generator of the locomotive type, the combination with thefire-box of such generator, of Water-tubes locatedl within saidtire-box, and coupling devices provided in the inner wall of the re-boxadapted to thrust the ends of the tubes endwise and to connect them in adetachable manner to said inner Wall, substantially as described.

5. In a steam-generator of the locomotive type the combination with theiire-box of such generator,of water-tubes located within said fire-box,hollow plugs or nipples screwed into the inner shell of the fire-boxfrom the inside and adapted to form seatings at their inner ends, theends of the said tubes being adapted to form a joint with said seatings,and coup-- ling nuts within the fire-box adapted to tighten the ends ofthe tubes against the said seatings, substantially as described.

6. In a steam-generatorv of the locomotive type the conibinationwith there-boX of such generator, of water-tubes located within said tire-box,hollow plugs fixed in the wall of, and projecting inwardly into, theiire-boX, the projecting ends of each plug being externallyscrew-threaded and formed with a conical seating, and coupling-nuts eachthreaded in ternally at one portion to screw upon :the correspondingplug and provided at another portion of smaller diameter with internalscrewthreads of a different pitch to the others and adapted to screwupon the screw-threaded end portion of the adjacent water-tubes, theends of said water-tubes being coned correspondingly to the seatings onthe plugs, substantially as described.

In testimony whereof I have signed my name to this specication in thepresence of two subscribing witnesses.

WALTER MACKERSIE SMITH.

Witnesses:

RALPH J. RoBsoN, JOHN WEATHERBURN,

